Myogenin is a member of a family of myogenic genes that also includes MyoD. These genes encode a set of transcription factors that are essential for muscle development. Expression of myogenin is restricted to cells of skeletal muscle origin. Myogenin antibody has been shown to label human myogenin and label neonatal mouse, rat and cat tissues. Staining has also been found in myoblasts from human fetal limbs. No reactivity was found in adult skeletal muscle. Myogenin has been observed to stain the vast majority of rhabdomyosarcomas and Wilm’s tumors. No activity was observed in Ewing’s sarcoma/peripheral primitive neuroectodermal tumor, or in neuroblastomas.